1. Field of the Invention
The present invention relates to a surface plasmon resonance sensing device and, more particularly, to a surface plasmon resonance sensing device which is portable, and the resonant wavelength of the fiber sensing unit thereof being within the transmission range of a single-mode fiber or the transmission range of a multi-mode fiber.
2. Description of Related Art
For applications in medical and environmental detection, it is essential to identify the species and concentrations of the biomolecules rapidly and accurately. For example, in environmentally hazardous occasions, the responding staff must first identify the species and the concentrations of the harmful materials at the site, so as to decide the subsequent procedures of treatment according to the detection results and minimize the risks of the treatment. Thus, accuracy, sensitivity, simplicity in operation procedures and portability are important.
To date, surface plasmon resonance sensing devices based on surface plasmon resonance effects have been employed by the industry to detect the species and the concentrations of the targeted biomolecules. The surface plasmon resonance sensing device possesses the following advantages: a. minimal time is required for detection; b. the sample is label-free during the detection process; c. minimal amount of the sample is required; d. detecting the interactions between the sample and the ligands thereof in real-time; and, e. high detection sensitivity.
FIG. 1 is a schematic illustration of the conventional surface plasmon resonance sensing device, including an incident light source 11, an incident light treatment unit 12, a prism 13, a metal layer 14, an optical detector 15, a detecting target loading unit 16 and a spectrometer 17, wherein the incident light source 11 is a laser diode, and the incident light treatment unit 12 further comprising a beam amplifier 121, a polarizer 122, a spectroscope 123 and a focus lens 124. Therefore, after light generated by the incident light source 11 passes through the incident light treatment unit 12, it has certain frequency, mode and polarization, which is suitable to be used in the detection process. Besides, the metal layer 14 is formed on the back surface of prism 13 by depositing gold or silver particles, either by vapor deposition or sputtering. In the course of detection, the light generated by the incident light source 11 first passes through the incident light treatment unit 12 and then enters a first side 131 of the prism 13. The light is reflected by the metal layer 14, then is emitted from a second side 132 of prism 13, and enters the optical detector 15. Finally, the optical signals received by the optical detector 15 are correspondingly converted to electrical signals, which are provided to spectrometer 17 for analysis of the spectrum profiles thereof.
However, the size of this kind of surface plasmon resonance sensing device is huge, and the locations of the components relative to each other must be maintained accurately, or the light emitting from the incidence light treatment unit will not be correctly reflected by the metal layer formed on the back surface of the prism, and the light will not reach the optical detector. Therefore, the conventional surface plasmon resonance sensing devices have low tolerance to vibrations and are easily damaged by collision, rendering them inappropriate for bringing to the impacted sites by the responding staff.
Furthermore, since the resonant wavelength of the fiber sensing unit of the conventional surface plasmon resonance sensing device is far away from the transmission range of a single-mode fiber or the transmission range of a multi-mode fiber, the surface plasmon resonance signal cannot be transmitted effectively from the fiber sensing unit to the single-mode fiber (or the multi-mode fiber) connected therewith, resulting in signals being lost to a certain level. As a result, the efficiency and the accuracy of the detection of the conventional surface plasmon resonance sensing device are impaired.
Therefore, a surface plasmon resonance sensing device that is portable, easy to operate, having a fiber sensing unit whose resonant wavelength being within the transmission range of a single-mode fiber or the transmission range of a multi-mode fiber, and capable of allowing the responding staff to bring the same to the impacted sites and proceed with accurate detection, is thus required.